Objective: To document the mortality and morbidity of infants weighing 501-1500 g at birth according to gestational age, birthweight, and sex.
Study design: Prospective collection of perinatal events and neonatal course to 120 days of life, discharge, or death from January 1990 through December 2002 for infants born at 16 participating centers of the National Institute of Child Health & Human Development Neonatal Research Network.
Results: Compared with 1995-1996, for 1997-2002 the survival of infants with birthweight of 501-1500 g increased by 1 percentage point (from 84% to 85%). Survival without major neonatal morbidity remained static, at 70%; this includes bronchopulmonary dysplasia (BPD), intraventricular hemorrhage (IVH), and necrotizing enterocolitis (NEC). Survival increased for multiple births (26%, up from 22%), antenatal corticosteroid use (79%, up from 71%), and maternal antibiotics (70%, up from 62%) (P < .05). From 1997 to 2002, birthweight-specific survival was 55% for infants weighing 501-750 g, 88% for 751-1000 g, 94% for 1001-1250 g, and 96% for 1251-1500 g. More females survived. The incidence of NEC (7%), severe IVH (12%), and late-onset septicemia (22%) remained essentially unchanged, but BPD decreased slightly, from 23% to 22%. The use of postnatal corticosteroids declined from 20% in 1997-2000 to 12% in 2001-2002. Growth failure (weight <10th percentile) at 36 weeks' postmenstrual age decreased from 97% in 1995-1996 to 91% in 1997-2002.
Conclusion: There have been no significant increases in survival without neonatal and long-term morbidity among VLBW infants between 1997 and 2002. We speculate that to improve survival without morbidity requires determining, disseminating, and applying best practices using therapies currently available, and also identifying new strategies and interventions.